Reenforced-concrete slab



March 24, 1931. T. J. OWEN 1,797,295

REENFORCED CONCRETE SLAB Filed Dec. 27, 1928 vPatented Mar. 24, 1931 r-ATELNT' l, or rice d,

THOMAS J. owEN, orAxRoN, OHIOV REENFORCED-CONCRETE SLAB f Application f11ed December 27, 1928. Serial-lilo;328,730.A

This'invention, which relates to reenforced concrete building structures, has for its b-A ject to provide an improved slab of light and strong construction adapted for floors or roofs and more particularly the latter.

Of the accompanying drawings, Fig. 1 is an elevation, partly in section, showinga portion of a sloping roof structure embodying slabsy constructed according to my invention.

kFigl 2 is an end view of one of the slabs on alarger scale.

Fig?) is a reverse plan view showing a portion on one of the slabs, partly in horizontal section.

My improved slab may be used inhorizon- A tal floors or roofs or in sloping roofs, and in Fig. 1 I have shown a portion of a sloping vroof having a frame-work including rafter vbeams such asflO and metallic I-beams or purlins 11 placed crosswise thereof to support the several roof slabs 12 which are placed with their side edges adjacent across the spaces between the beams 11 to formy t' throughout their length, these ribs projecting below the vweb 13 preferably to a somewhat greater distance than the thickness of the web. The ends of the ribs are longitudinally recessed at 15 for less than their full depth to form ledges or seats 16 for resting on the I-beams 11, and shoulders 17 to abut against the anges of said beams for holding the slab 1 v v,

` the ends' ofthe slab are concentrated under against longitudinal displacement. The upper edges of the slab at the ends thereof may further be formed with shallow ledges 18 as an incident to the particular form of mold employed in'casting the slab, but these ledges are not an essential structural feature. A

Embedded longitudinally in the slab 12, re-

' spectively coincident with theseveral ribs 14,

5 areV a series Vofmetallic reenforcing rods' or The slab 12 is formed with a top web 13 and bars 19 preferably of the twisted, ribbed type and preferably t having their extremities 2Q turned or hooked at rightfangles in the plane of the slab toV afford anchorage in the concrete for said rods from the very'ends of the rods, which ends extend into the end portions of the slab over the. seating faces 16of the ribs.V These rods are positioned intheconcrete at depths varying throughout the length of the slab from a minimum at 'the ends to a maximum in the middle, and are given substantially a catenary ,orfunicular curve by bending v'from van original straight condition down into the concrete'during the v*formaties of the slab so they will constitute tension truss members-while leaving the rods covered witha sufficient thickness of concrete to comply with building regulations.

Y Theconcretebody may be made ywithvthe usual proportions of Portland cement and coarse and fine mineralaggregate, and `for the latter l prefer to employ a light and somewhat porous, artificial-stone such as the material knowin asHaydite or its equivalent, this being'a relatively light and strong, sin` tered, stone-like, clay product about 8 tor 9% of which will float 'whenplaced in .water so that the collective speciiicvgravity Vof such material but slightly exceeds that of Water. rlhis aggregate-may be employed in; grades having the particle size respectively of gravelY andsand, and, its use in this connectiomtogether withv the structural features described, affords an exceptionally Vlight and strongtreenforced slabispeculiarly suited for roofing purposes, the necessarystrength 4factor being, obtained with theminimum amount of Vreenforcing metal and at a relatively low cost.

It will be noted that by notching the. ends of lthe ribs 14 for. less than their full depth to. form supporting seats, the `supports for thev ends ofthe reenforcing bars 19, expansion and contraction at varying temperatures are allowed in all directlons, and an even, collective .top surface is provided by'reducingv l the opportunity forirregularitiesbetween the seating surfacesand the supporting beams.

A'roof thus constructedfmay be finished with fthe usual bituminous 0r other suitable coating overlying the slabs and covering their intervening joints.

While I have described a preferred embodiment of my invention7 it will be understood `that the detailsmay be more or less varied Within the scope of the appended claims.

I claim: f l. A building slab of elongated form comprising a concrete body including a top web l having a series of longitudinal ribs formed body including a top web and a series of ribs formed on the lower side thereof and recessed at their ends to provide seating surfaces, and reenforcing bars located substantially wholly within said ribs and extended into their ends over said seat-ing surfaces.

In witness whereof I have hereunto set my hand this 22d day of December, 1928.

- THOMAS J. OWEN. 75

on its lower side and extended into the ends to form seating portions, and a series of metending into the end seating portions of the A slab.

3. A building slab comprising a concrete body including a top web having a series of ribs formed on its lower side and recessed at their ends for less than the full depth 0f the ribs to form a plurality of seating surfaces,

and metallic reenforcingV elementsy embedded in the slab coincident with the ribs and extelnding into the seating portions of said r1 s. Y

4. A building slab comprising a concrete body including a topweb-having a series of ribs formed on itslower side and recessed at their ends for less than the full depth of the ribs to form a plurality of Yseating surfaces at each end of the slab, and a series of metallic, twisted, ribbed,-truss bars embedded in said ribs andextending into the seatingV portions thereof.

5. A building slab comprising an elongated concrete body'including a top web having a series ofY longitudinal `ribs formed on its lower side, and a series of metallic truss bars embedded in Vsaid ribs and extending into the seating portions at the ends of the slab, said bars having anchoring extremitiesV bent at an angle in the plane of the slab.

6. A building slab comprising an elongated concrete body including atop web having a series of longitudinal ribs formed on its lower sideand recessedaty their ends for less than the full depth of the ribs to form a plurality of seating surfaces at each end of the slab, said ribs being of substantially uniform depth throughout their length except at the ends,

and a series of metallic, twisted, ribbed, truss bars embedded substantially.v in catenary curves in said ribs and having anchoring extremities bent at an angle in the plane of Ythe slab over said seating surfaces.

7 A building slab. comprising a concrete 

